Audio, video, and data recording devices are well known and of several varieties. Magnetic tape, magnetic and optical disk, are just some of the well known mediums for devices which may record and playback such data. More recently, the ability to record and playback information using a solid-state RPM and memory device has been achieved. Integrated circuit (IC) companies for example, have recently introduced audio Record/Playback Modules (RPMs) on a single Very Large Scale Integration (VLSI) integrated circuit. By the addition of solid-state memory, devices have been constructed which record and playback or just playback audio signals.
Unlike their magnetic, optical, and similar medium counterparts, these devices have no moving parts to wear out. They have been used in many applications which include public safety annunciators, point-of-sale advertising, phone message devices, and other message repeater devices. In general, the message device or SSRPD has a trigger input to activate the message and a signal output which is usually a speaker or analog line output which may be connected to another signal input such as a power amplifier.
Although much of this disclosure of this invention refers to audio and similar analog information as the message information it should be understood that this invention is not limited to audio and is intended to cover a much broader spectrum. Most of the record/playback VLSIs currently available are audio devices. Video and/or audio VLSI devices are on the horizon, however, RPMs may currently be constructed with discrete circuitry and building blocks that may perform the same types of functions with audio, video, and other data in the same or similar manner as currently available audio VLSIs.
With regard to message devices, RPMs and SSRPDs, there are basically two types of devices currently available. The first type is a playback-only device (POD), which contains a read only memory (ROM). The message information is programmed into the memory device by a separate development system. In the case of electrically programmable read only memory (EPROM) or electrically erasable programmable read only memory (EEPROM), the memory device may only be programmed or reprogrammed by the development system. The POD may only read (playback) from the memory but cannot write (record) to it. Messages may be changed in the POD by replacing the memory device, but that new memory device must stay with the machine. This is often accomplished by inserting the programmed memory circuitry into a connector socket or using a cartridge which plugs into a connector resident in the POD. Therefore, if it is desired to change messages in 100 machines one must replace the memories in the 100 machines with 100 newly programmed or reprogrammed memories. The necessity having to produce individual memory devices for each playback unit is a significant and relevant shortcoming of this type of arrangement. Another shortcoming with these devices is the development system. One must have a development system to program messages into memory. These systems generally consist of a computing device, special software, and a programmer device to program the memories.
The second type of device that currently exists is the stand alone SSRPD. These devices contain a resident memory which may be written to (record) as well as read from (playback). The SSRPD contains a Record/Playback Module (RPM), which performs all of the record signal conversion such as analog to digital (A/D), recording and data compression algorithms, digital signal processing, and playback signal conversion such as digital to analog (D/A). In general, the resident memory is directly connected to the RPM rather than part of a more complex bus architecture.
These units have an analog input(s) to be able to record source information, and analog output(s) which provide the message output. However, these devices have no means for transferring message and other information in its digital form. Since these devices only contain analog inputs and outputs, the only way to exchange information from one unit to another is through a separate record/playback device with an analog input and output. For example, a tape recorder might be used to copy from one unit to others but the conversion from digital to analog, copying to tape, and then converting analog to digital in another SSRPD causes degradation. The lack of a direct digital transfer interface also requires that another record/playback device such as a tape recorder is needed to archive message information. This is a cumbersome and nonefficient method for archiving and retrieving messages.
Many of these SSRPD's have an analog input such as a microphone input for changing messages in the field. But the field may be a noisy environment and would produce less than desirable results compared to a quiet studio type of environment. An audio line input is often provided on currently available units. This is more direct and helps eliminate the noise problems associated with a microphone however, another record/playback device such as a tape recorder is still needed to transfer and archive message information. Furthermore, this process is also very slow in that it happens in real time. Thus, changing a ten minute analog message would take ten minutes to download, and ten minutes of upload time at each SSRPD.
Although many of the currently available devices have simple trigger inputs such as a single contact(s) or switch closure or open-collector transistor level change, they do not have a sophisticated analog and/or digital program input(s) processor and bus architecture for interactive as well as non-interactive control. They also do not have a time and control processor which may perform sophisticated internal timing and control, as well as interface to other devices through an accepted digital interface such as the Musical Instrument Digital Interface (MIDI) standard, Society of Motion Picture and Television Engineers (SMPTE) interface standard, Small Computer Systems Interface (SCSI), RS-232, networks such as ethernet, neural networks and the like. These external devices with which communications would be performed may include but are not limited to; other SSRPDs, computers, robotics, musical instruments, lighting controllers, appliances and the like. The currently available devices also cannot perform sequencer functions so that several devices may be linked together and synchronized using MIDI, RS-422, SMPTE and the like. This would be useful for example, where several SSRPDs are spread out in an animation and lighting show which might include robots, light controllers, MIDI instruments, and audio/video animatronics.
Conversely, although some of the currently available devices have a simple output signal(s) such as open collector transistor logic, they do not have a sophisticated control output processing module that interfaces via bus architecture with the other elements of the SSRPD, and provides analog and/or digital control of another device(s). Control of a different type of device such as an animation robot, computer, or other SSRPD which is synchronized to the time and control processor would be a desirable capability.
Another problem with currently available message devices and SSRPD's is that inherent within the RPM and related circuitry there may be a significant error signal(s) which is not desirable as a part of the message information. For example, in currently available audio record/playback or playback-only VLSI integrated circuits which are the heart of the SSRPD or POD, there exists a DC offset voltage in the record and/or playback circuitry. These offset voltages are an inherent part of the VLSI fabrication and although they may vary in level from one IC to another, they cause an undesirable effect of a popping noise at the beginning and end of playback. This may not be significant with lower offset IC's and low gain audio systems, but may become very significant when higher offset ICs are used with high gain audio systems. The popping noise is not only annoying but may also in extreme cases damage a speaker or amplifier. Additional circuitry such as analog summing circuitry may be added externally to the VLSI to sum in correction voltages, but this adds to cost and circuit complexity. There is no current means for removing this error without-the addition of correction circuitry.
Most of the playback only devices as well as SSRPD's have a trigger input for triggering message play. There are many possible trigger sources from a simple relay or switch contact closure to a sensor trigger such as a motion sensor. In either case the message device is triggered by a simple level or edge trigger. If the source is a more complicated device such as a motion sensor the output of the motion sensor electronics must be a simple level or edge trigger to interface properly with the message device. A means for adjusting the sensitivity of the threshold for triggering to accommodate various complex and multiple trigger sources and accept different trigger levels for each is not available on current message devices. Therefore, if a different trip level sensitivity is desired it may only be accomplished by changes to the trigger source itself. Furthermore, there is no sophisticated time and control and program input processing on the currently available devices to provide a much more flexible means for synchronization and triggering.
There are many cases where it is desirable to operate an SSRPD on batteries. Furthermore, several applications require portability. Most of the currently available devices may be operated from alternating current (AC) power and many have DC power inputs. These devices however, are generally not designed for low power consumption. There are inexpensive PODs available such as talking watches, that operate from batteries are often in an off or sleep state when they-are not in use to conserve battery life. A simple trigger as previously described may be used to wake them up, playback the message then return to sleep or turn off. With currently available devices however, there is no capability to operate in a low power active sleep mode whereby the SSRPD may actively look for a trigger at predetermined intervals, sample the trigger source and only if it meets a given predetermined trigger criteria, awake, play the message, then revert to the low power state. This is especially useful when interfacing with more sophisticated sensors such as motion sensors.
It is thus apparent that a need exists for a message device and SSRPD which may record and playback information such as message, internal and external control, timing and synchronization, program input, and program output information using resident solid-state memory(s).
It is also apparent that a need exists for a message device and SSRPD with an interface for direct and efficient exchange of message and other information without degradation.
It is also advantageous to use this interface for exchanging the information with other SSRPDs and other devices such as a CID via a portable storage device.
It is further advantageous to be able to use this interface or other separate interfaces for simultaneous control or communication with other devices such as animated robots, computers, other SSRPD's and the like.
It is also apparent that the need exists for a message device and. SSRPD which may master and transfer information without degradation through a PSD or other digital interfaces, and which does not require a special development system or require that a device's resident memory(s) be replaced or reprogrammed by a development system to change message and/or other information.
It is further apparent that the need exists for an intelligent computer interface device that may work with any standard computer or dumb terminal and provide lossless reading, writing, editing, and efficient archiving and retrieving of PSD information without the need of a special development system.
It is further desirable for the CID and computer or dumb terminal to be able to perform diagnostic procedures on the PSD and SSRPD.
It is also apparent that the need exists for a method to remove undesirable error signals from the SSRPD without the need for error correction circuitry. It is further advantageous to make this correction without any adverse effect when information is transferred via PSD or other means from one SSRPD to another.
It is also apparent that the need exists for a message device and SSRPD whereby trigger sensitivity and may be adjusted by the SSRPD rather than the sensor or sensor electronics.
Finally, it is apparent that the need exists for a message device and SSRPD which may operate in a low power active sleep mode that may actively look for a trigger at predetermined intervals, Sample the trigger source and only if it meets a given predetermined trigger criteria, awake, playback the message and other information, then revert to the low power state.